Identification of human exTreg cells as CD16+CD56+ cytotoxic CD4+ T cells.

In atherosclerosis, some regulatory T (Treg) cells become exTreg cells. We crossed inducible Treg and exTreg cell lineage-tracker mice (FoxP3eGFP-Cre-ERT2ROSA26CAG-fl-stop-fl-tdTomato) to atherosclerosis-prone Apoe-/- mice, sorted Treg cells and exTreg cells and determined their transcriptomes by bulk RNA sequencing (RNA-seq). Genes that were differentially expressed between mouse Treg cells and exTreg cells and filtered for their presence in a human single-cell RNA-sequencing (scRNA-seq) panel identified exTreg cell signature genes as CST7, NKG7, GZMA, PRF1, TBX21 and CCL4. Projecting these genes onto the human scRNA-seq with CITE-seq data identified human exTreg cells as CD3+CD4+CD16+CD56+, which was validated by flow cytometry. Bulk RNA-seq of sorted human exTreg cells identified them as inflammatory and cytotoxic CD4+T cells that were significantly distinct from both natural killer and Treg cells. DNA sequencing for T cell receptor-ß showed clonal expansion of Treg cell CDR3 sequences in exTreg cells. Cytotoxicity was functionally demonstrated in cell killing and CD107a degranulation assays, which identifies human exTreg cells as cytotoxic CD4+T cells.

A mechanism for hereditary angioedema caused by a methionine-379-to-lysine substitution in kininogens.

ABSTRACT: Hereditary angioedema (HAE) is associated with episodic kinin-induced swelling of the skin and mucosal membranes. Most patients with HAE have low plasma C1-inhibitor activity, leading to increased generation of the protease plasma kallikrein (PKa) and excessive release of the nanopeptide bradykinin from high-molecular-weight kininogen (HK). However, disease-causing mutations in at least 10% of patients with HAE appear to involve genes for proteins other than C1-inhibitor. A point mutation in the Kng1 gene encoding HK and low-molecular weight kininogen (LK) was identified recently in a family with HAE. The mutation changes a methionine (Met379) to lysine (Lys379) in both proteins. Met379 is adjacent to the Lys380-Arg381 cleavage site at the N-terminus of the bradykinin peptide. Recombinant wild-type (Met379) and variant (Lys379) versions of HK and LK were expressed in HEK293 cells. PKa-catalyzed kinin release from HK and LK was not affected by the Lys379 substitutions. However, kinin release from HK-Lys379 and LK-Lys379 catalyzed by the fibrinolytic protease plasmin was substantially greater than from wild-type HK-Met379 and LK-Met379. Increased kinin release was evident when fibrinolysis was induced in plasma containing HK-Lys379 or LK-Lys379 compared with plasma containing wild-type HK or LK. Mass spectrometry revealed that the kinin released from wild-type and variant kininogens by PKa is bradykinin. Plasmin also released bradykinin from wild-type kininogens but cleaved HK-Lys379 and LK-Lys379 after Lys379 rather than Lys380, releasing the decapeptide Lys-bradykinin (kallidin). The Met379Lys substitutions make HK and LK better plasmin substrates, reinforcing the relationship between fibrinolysis and kinin generation.

Allosteric Activation Dictates PRC2 Activity Independent of Its Recruitment to Chromatin.

PRC2 is a therapeutic target for several types of cancers currently undergoing clinical trials. Its activity is regulated by a positive feedback loop whereby its terminal enzymatic product, H3K27me3, is specifically recognized and bound by an aromatic cage present in its EED subunit. The ensuing allosteric activation of the complex stimulates H3K27me3 deposition on chromatin. Here we report a stepwise feedback mechanism entailing key residues within distinctive interfacing motifs of EZH2 or EED that are found to be mutated in cancers and/or Weaver syndrome. PRC2 harboring these EZH2 or EED mutants manifested little activity in vivo but, unexpectedly, exhibited similar chromatin association as wild-type PRC2, indicating an uncoupling of PRC2 activity and recruitment. With genetic and chemical tools, we demonstrated that targeting allosteric activation overrode the gain-of-function effect of EZH2Y646X oncogenic mutations. These results revealed critical implications for the regulation and biology of PRC2 and a vulnerability in tackling PRC2-addicted cancers.

From pollutant to powerhouse: The untapped potential of sewage sludge and wastewater.

Advances in science and technology that enable the recovery of energy and other valuable compounds from sewage sludge can play an important role in a global transition to renewable energy sources.

Extraordinary Electrical Conductance through Amorphous Nonconducting Polymers under Vibrational Strong Coupling.

Enhancing the electrical conductance through amorphous nondoped polymers is challenging. Here, we show that vibrational strong coupling (VSC) of intrinsically nonconducting and amorphous polymers such as polystyrene, deuterated polystyrene, and poly(benzyl methacrylate) to the vacuum electromagnetic field of the cavity enhances the electrical conductivity by at least 6 orders of magnitude compared to the uncoupled polymers. Remarkably, the observed extraordinary conductance is vibrational mode selective and occurs only under the VSC of the aromatic C-H(D) out-of-plane bending modes of the polymers. The conductance is thermally activated at the onset of strong coupling and becomes temperature-independent as the collective strong coupling strength increases. The electrical characterizations are performed without external light excitation, demonstrating the role of vacuum electromagnetic field-matter strong coupling in enhancing long-range transport even in amorphous nonconducting polymers.

MzDOCK: A free ready-to-use GUI-based pipeline for molecular docking simulations.

Molecular docking is by far the most preferred approach in structure-based drug design for its effectiveness to predict the scoring and posing of a given bioactive small molecule into the binding site of its pharmacological target. Herein, we present MzDOCK, a new GUI-based pipeline for Windows operating system, designed with the intent of making molecular docking easier to use and higher reproducible even for inexperienced people. By harmonic integration of python and batch scripts, which employs various open source packages such as Smina (docking engine), OpenBabel (file conversion) and PLIP (analysis), MzDOCK includes many practical options such as: binding site configuration based on co-crystallized ligands; generation of enantiomers from SMILES input; application of different force fields (MMFF94, MMFF94s, UFF, GAFF, Ghemical) for energy minimization; retention of selectable ions and cofactors; sidechain flexibility of selectable binding site residues; multiple input file format (SMILES, PDB, SDF, Mol2, Mol); generation of reports and of pictures for interactive visualization. Users can download for free MzDOCK at the following link: https://github.com/Muzatheking12/MzDOCK.

Fluorine-Free MXenes: Recent Advances, Synthesis Strategies, and Mechanisms.

MXenes, an exceptional class of 2D materials, possess high conductivity, adaptable surface chemistry, mechanical strength, and tunable bandgaps, making them attractive for diverse applications. Unlocking the potential of MXenes requires precise control over synthesis methods and surface functionality. Conventionally, fluorine-based etchants are used in MXenes synthesis, posing both environmental concerns and alterations to surface properties, along with the introduction of certain defects. This prompts the exploration of innovative fluorine-free strategies for MXenes synthesis. This review focuses on environmentally friendly, fluorine-free techniques for MXene synthesis, emphasizing mechanisms and recent breakthroughs in alternative etching strategies. The comprehensive coverage includes electrochemical etching, Lewis acid-driven molten salt etching, alkaline/hydrothermal techniques, chemical vapor deposition (CVD), and recent innovative methods. Fluorine-free MXenes synthesis yields terminations such as ─O, ─OH, ─Cl, etc., influencing surface chemistry and improving their properties. The presence of ─OH groups in NaOH etched MXenes boosts their energy storage, while ─Cl functionality from Lewis acidic salts optimizes electrochemical performance. Fluorine-free methods mitigate adverse effects of ─F terminations on MXene conductivity, improving electronic properties and broadening their applications. In addition to traditional approaches, this review delves into novel fluorine-free methods for tailoring MXenes properties. It comprehensively addresses challenges, opportunities, and future perspectives in fluorine-free MXenes.

Risk of flare and damage accrual after tapering glucocorticoids in modified serologically active clinically quiescent patients with systemic lupus erythematosus: a multinational observational cohort study.

OBJECTIVES: To assess the risk of flare and damage accrual after tapering glucocorticoids (GCs) in modified serologically active clinically quiescent (mSACQ) patients with systemic lupus erythematosus (SLE). METHODS: Data from a 12-country longitudinal SLE cohort, collected prospectively between 2013 and 2020, were analysed. SLE patients with mSACQ defined as the state with serological activity (increased anti-dsDNA and/or hypocomplementemia) but without clinical activity, treated with ≤7.5 mg/day of prednisolone-equivalent GCs and not-considering duration, were studied. The risk of subsequent flare or damage accrual per 1 mg decrease of prednisolone was assessed using Cox proportional hazard models while adjusting for confounders. Observation periods were 2 years and censored if each event occurred. RESULTS: Data from 1850 mSACQ patients were analysed: 742, 271 and 180 patients experienced overall flare, severe flare and damage accrual, respectively. Tapering GCs by 1 mg/day of prednisolone was not associated with increased risk of overall or severe flare: adjusted HRs 1.02 (95% CI, 0.99 to 1.05) and 0.98 (95% CI, 0.96 to 1.004), respectively. Antimalarial use was associated with decreased flare risk. Tapering GCs was associated with decreased risk of damage accrual (adjusted HR 0.96, 95% CI, 0.93 to 0.99) in the patients whose initial prednisolone dosages were >5 mg/day. CONCLUSIONS: In mSACQ patients, tapering GCs was not associated with increased flare risk. Antimalarial use was associated with decreased flare risk. Tapering GCs protected mSACQ patients treated with >5 mg/day of prednisolone against damage accrual. These findings suggest that cautious GC tapering is feasible and can reduce GC use in mSACQ patients.

Botanicals as promising antimicrobial agents for enhancing oral health: a comprehensive review.

The mouth houses the second largest diversity of microorganisms in the body, harboring more than 700 bacterial species colonizing the soft mucosa and hard tooth surfaces. Microbes are the cause of several health-related problems, such as dental carries, gingivitis, periodontitis, etc., in the mouth across different age groups and socioeconomic/demographic groups. Oral infections are major health problems that affect the standard of living. Compromised oral health is related to chronic conditions and systemic disorders. Microbes responsible for dental caries are acid-producing and aciduric Gram-positive bacteria (Streptococci, Lactobacilli). Gram-negative bacteria (Porphyromonas, Prevotella, Actinobacillus, and Fusobacterium) capable of growing in anaerobic environments are responsible for periodontal diseases. Due to the high prevalence of oral diseases, negative effects associated with the use of antimicrobial agents and increased antibiotic resistance in oral pathogens, suitable alternative methods (effective, economical and safe) to suppress microbes disturbing oral health need to be adopted. Side effects associated with the chemical antimicrobial agents are vomiting, diarrhea and tooth staining. Several researchers have studied the antimicrobial properties of plant extracts and phytochemicals and have used them as indigenous practices to control several infections. Therefore, phytochemicals extracted from plants can be suitable alternatives. This review focuses on the various phytochemical/plant extracts suppressing the growth of oral pathogens either by preventing their attachment to the surfaces or by preventing biofilm formation or other mechanisms.

SMART-SLE: serology monitoring and repeat testing in systemic lupus erythematosus-an analysis of anti-double-stranded DNA monitoring.

OBJECTIVE: Disease activity monitoring in SLE includes serial measurement of anti-double stranded-DNA (dsDNA) antibodies, but in patients who are persistently anti-dsDNA positive, the utility of repeated measurement is unclear. We investigated the usefulness of serial anti-dsDNA testing in predicting flare in SLE patients who are persistently anti-dsDNA positive. METHODS: Data were analysed from patients in a multinational longitudinal cohort with known anti-dsDNA results from 2013 to 2021. Patients were categorized based on their anti-dsDNA results as persistently negative, fluctuating or persistently positive. Cox regression models were used to examine longitudinal associations of anti-dsDNA results with flare. RESULTS: Data from 37 582 visits of 3484 patients were analysed. Of the patients 1029 (29.5%) had persistently positive anti-dsDNA and 1195 (34.3%) had fluctuating results. Anti-dsDNA expressed as a ratio to the normal cut-off was associated with the risk of subsequent flare, including in the persistently positive cohort (adjusted hazard ratio [HR] 1.56; 95% CI: 1.30, 1.87; P < 0.001) and fluctuating cohort (adjusted HR 1.46; 95% CI: 1.28, 1.66), both for a ratio >3. Both increases and decreases in anti-dsDNA more than 2-fold compared with the previous visit were associated with increased risk of flare in the fluctuating cohort (adjusted HR 1.33; 95% CI: 1.08, 1.65; P = 0.008) and the persistently positive cohort (adjusted HR 1.36; 95% CI: 1.08, 1.71; P = 0.009). CONCLUSION: Absolute value and change in anti-dsDNA titres predict flares, including in persistently anti-dsDNA positive patients. This indicates that repeat monitoring of dsDNA has value in routine testing.

Malignant Chest Wall Tumors: Complex Defects and Their Management-A Review of 181 Cases.

BACKGROUND: Chest wall tumors are a heterogeneous group of tumors that are managed by surgeons from diverse specialties. Due to their rarity, there is no consensus on their diagnosis and management. MATERIALS: This retrospective, descriptive analysis includes patients with malignant chest wall tumors undergoing chest wall resection. Tumors were classified as primary, secondary, and metastatic tumors. The analysis includes clinicopathological characteristics, resection-reconstruction profile, and relapse patterns. RESULTS: A total of 181 patients underwent chest wall resection between 1999 and 2020. In primary tumors (69%), the majority were soft tissue tumors (59%). In secondary tumors, the majority were from the breast (45%) and lung (42%). Twenty-five percent of patients received neoadjuvant chemotherapy, and 98% of patients underwent R0 resection. Soft tissue, skeletal + soft tissue, and extended resections were performed in 45%, 70%, and 28% of patients, respectively. The majority of patients (60%) underwent rib resections, and a median of 3.5 ribs were resected. The mean defect size was 24 cm2. Soft tissue reconstruction was performed in 40% of patients, mostly with latissimus dorsi flaps. Rigid reconstruction was performed in 57% of patients, and 18% underwent mesh-bone cement sandwich technique reconstruction. Adjuvant radiotherapy and chemotherapy were given to 29% and 39% of patients, respectively. CONCLUSIONS: This is one of the largest single-institutional experiences on malignant chest wall tumors. The results highlight varied tumor spectra and multimodality approaches for optimal functional and survival outcomes. In limited resource setting, surgery, including reconstructive expertise, is very crucial.

A mechanism for hereditary angioedema caused by a lysine 311-to-glutamic acid substitution in plasminogen.

Patients with hereditary angioedema (HAE) experience episodes of bradykinin (BK)-induced swelling of skin and mucosal membranes. The most common cause is reduced plasma activity of C1 inhibitor, the main regulator of the proteases plasma kallikrein (PKa) and factor XIIa (FXIIa). Recently, patients with HAE were described with a Lys311 to glutamic acid substitution in plasminogen (Plg), the zymogen of the protease plasmin (Plm). Adding tissue plasminogen activator to plasma containing Plg-Glu311 vs plasma containing wild-type Plg (Plg-Lys311) results in greater BK generation. Similar results were obtained in plasma lacking prekallikrein or FXII (the zymogens of PKa and FXIIa) and in normal plasma treated with a PKa inhibitor, indicating Plg-Glu311 induces BK generation independently of PKa and FXIIa. Plm-Glu311 cleaves high and low molecular weight kininogens (HK and LK, respectively), releasing BK more efficiently than Plm-Lys311. Based on the plasma concentrations of HK and LK, the latter may be the source of most of the BK generated by Plm-Glu311. The lysine analog ε-aminocaproic acid blocks Plm-catalyzed BK generation. The Glu311 substitution introduces a lysine-binding site into the Plg kringle 3 domain, perhaps altering binding to kininogens. Plg residue 311 is glutamic acid in most mammals. Glu311 in patients with HAE, therefore, represents reversion to the ancestral condition. Substantial BK generation occurs during Plm-Glu311 cleavage of human HK, but not mouse HK. Furthermore, mouse Plm, which has Glu311, did not liberate BK from human kininogens more rapidly than human Plg-Lys311. This indicates Glu311 is pathogenic in the context of human Plm when human kininogens are the substrates.

Interleukin-7 potentiates MAPK10-elicited host-protective vaccine against Leishmania donovani.

Leishmania donovani causes the potentially fatal disease visceral leishmaniasis for which neither a vaccine nor an adjuvant for human use exists. Although interleukin-7 (IL-7) is implicated in CD4+ T-cell response stabilization, its anti-leishmanial function is uncertain. Therefore, we examined whether IL-7 would potentiate the efficacy of Leishmania major-expressed MAPK10 (LmjMAPK10; M10)-elicited anti-leishmanial host-protective response. We observed that aligning with IL-7R expression, IL-7 increased IFN-γ-secreting TH1 cell but reduced IL-4-producing TH2 cells and production of IL-10 and TGF-ß effectuating anti-leishmanial functions in susceptible BALB/c mouse-derived macrophages. Co-culturing IL-7-pre-treated L. donovani-infected macrophages with L. donovani-infected BALB/c-derived T cells induced IFN-γ-dominated TH1 type anti-leishmanial function. IL-7 treatment of L. donovani-infected BALB/c mice significantly reduced splenic and hepatic parasite loads. Co-culturing CD4+ T cells from IL to 7-treated mice with L. donovani-infected macrophages reduced amastigote numbers suggesting IL-7-elicited host-protective effector T cells. Priming BALB/c with M10 + IL-7 reduced the splenic parasite burden more effectively than that was observed in M10-primed mice. An enhanced protection against L. donovani infection was accompanied by enhanced IL-12 and IFN-γ, but suppressed IL-10 and IL-4, response and host-protective TH1 and memory T cells. These results indicate IL-7-induced leishmanial antigen-specific memory T cell response that protects a susceptible host against L. donovani infection.

Impact of HPV strains on molecular mechanisms of cervix cancer.

PURPOSE: Cervical cancer accounts for a high number of deaths worldwide. Risk factors are extensive for cervix cancer but Human papillomavirus (HPV) plays a prime role in its development. Different strains of HPV are prevalent globally, which show different grades of mortality and morbidity among women. This study is planned to evaluate the molecular mechanism of different strains of HPV infection and progression leading to cervix cancer. METHODS: This review includes different research articles on cervix cancer progression reported from India and all over the world. RESULTS: HPV 16 and 18 are prevalent strains using heparan sulfate-independent and dependent pathways for viral replication inside the cell. It also uses transcription mechanisms through NF-kappa B, FOXA-1, and AP-1 genes while strains like HPV-35, 45, and 52 are also predominant in India, which showed a very slow mechanism of progression due to which mortality rate is low after their infection with these strains. CONCLUSION: HPV uses E6 and E7 proteins which activate NF-kappa B and AP-1 pathway which suppresses the tumor suppressor gene and activates cytokine production, causing inflammation and leading to a decrease in apoptosis due to Caspase-3 activation. In contrast, the E7 protein involves HOXA genes and decreases apoptotic factors due to which mortality and incidence rates are low in viruses that use E7 motifs. Some HPV strains employ the cap-dependent pathway, which is also associated with lower mortality and infection rates.

Comparison of Attainment and Protective Effects of Lupus Low Disease Activity State In Patients With Newly Diagnosed Versus Established Systemic Lupus Erythematosus.

OBJECTIVE: To assess whether Lupus Low Disease Activity State (LLDAS) attainment is associated with favorable outcomes in patients with recent onset systemic lupus erythematosus (SLE). METHODS: Data from a 13-country longitudinal SLE cohort were collected prospectively between 2013 and 2020. An inception cohort was defined based on disease duration < 1 year at enrollment. Patient characteristics between inception and noninception cohorts were compared. Survival analyses were performed to examine the association between LLDAS attainment and damage accrual and flare. RESULTS: Of the total 4106 patients, 680 (16.6%) were recruited within 1 year of SLE diagnosis (inception cohort). Compared to the noninception cohort, inception cohort patients were significantly younger, had higher disease activity, and used more glucocorticoids, but had less organ damage at enrollment. Significantly fewer inception cohort patients were in LLDAS at enrollment than the noninception cohort (29.6% vs 52.3%, P < 0.001), but three-quarters of both groups achieved LLDAS at least once during follow-up. Limiting analysis only to patients not in LLDAS at enrollment, inception cohort patients were 60% more likely to attain LLDAS (hazard ratio 1.37, 95% CI 1.16-1.61, P < 0.001) than noninception cohort patients and attained LLDAS significantly faster. LLDAS attainment was significantly protective against flare in both the inception and noninception cohorts. A total of 88 (13.6%) inception cohort patients accrued organ damage during a median 2.2 years of follow-up. CONCLUSION: LLDAS attainment is protective from flare in recent onset SLE. Significant protection from damage accrual was not observed because of low rates of damage accrual in the first years after SLE diagnosis. (ClinicalTrials.gov: NCT03138941).

Can cell-free DNA (cfDNA) in pleural lavage serve as a predictive and prognostic biomarker among surgically treated Stage I-III a nonsmall cell lung cancer (NSCLC)? A pilot study.

BACKGROUND AND OBJECTIVES: The role of cell-free DNA (cfDNA) in operable nonsmall cell lung cancer (NSCLC) is unclear. This study was aimed to evaluate the feasibility for identification of cfDNA in pleural lavage fluid and its correlation with plasma in resectable NSCLCs. METHODS: Consecutively resected NSCLCs were evaluated for cfDNA levels in preoperative plasma (PLS1), intraoperative pleural-lavage (PLV) and postoperative (at 1 month) plasma sample (PLS2). CfDNA was isolated and measured quantitatively by qPCR in a TaqMan probe-detection approach using the human ß-actin gene as the amplifying target. RESULTS: All (n = 34) except one were negative for malignant cells in PLV cytology. CfDNA could be isolated from all the three samples (PLS1, PLV, and PLS2) successfully in each patient. The median cfDNA levels in PLS1, PLV and PLS2 were 118 ng/mL (IQR 61-158), 167 ng/mL (IQR 59.9-179.9) and 103 ng/mL (IQR 66.5-125.4) respectively. The median follow-up was 34.1 months (IQR 25.2-41.6). A significant overall-survival (OS) and disease-free survival (DFS) were recorded for patients with cfDNA level cut-offs at 125, 170, and 100 ng/mL, respectively for PLS1, PLV, and PLS2. Patients with raised cfDNA in PLS1 (>125 ng/mL) and PLV (>170 ng/mL) had significantly poorer 2-year OS, p = 0.005 and p = 0.012, respectively. The hazards (OS) were also higher for those with raised cfDNA in PLV (HR = 5.779, 95% CI = 1.162-28.745, p = 0.032). PLV (>170 ng/mL) had increased pleural recurrences (p = 0.021) and correlated significantly with poorer DFS at 2-years (p = 0.001) with increased hazards (HR = 9.767, 95% CI = 2.098-45.451, p = 0.004). Multivariable analysis suggested higher cfDNA in PLV as a poor prognostic factor for both OS and DFS. CONCLUSIONS: Among patients with operable NSCLC, it is feasible to identify cfDNA in pleural lavage and correlate PLV cfDNA with pleural recurrences and outcomes.

Methyl jasmonate inducible UGT79A18 is a novel glycosyltransferase involved in the bacoside biosynthetic pathway in Bacopa monnieri.

Bacosides are dammarane-type triterpenoidal saponins in Bacopa monnieri and have various pharmacological applications. All the bacosides are diversified from two isomers, i.e., jujubogenin and pseudojujubogenin. The biosynthetic pathway of bacoside is not well elucidated. In the present study, we characterized a UDP-glycosyltransferase, UGT79A18, involved in the glycosylation of pseudojujubogenin. UGT79A18 shows higher expression in response to 5 h of wounding, and 3 h of MeJA treatment. The recombinant UGT79A18 shows in vitro activity against a wide range of flavonoids and triterpenes and has a substrate preference for protopanaxadiol, a dammarane-type triterpene. Secondary metabolite analysis of overexpression and knockdown lines of UGT79A18 in B. monnieri identify bacopasaponin D, bacopaside II, bacopaside N2 and pseudojujubogenin glucosyl rhamnoside as the major bacosides that were differentially accumulated. In the overexpression lines of UGT79A18, we found 1.7-fold enhanced bacopaside II, 8-fold enhanced bacopasaponin D, 3-fold enhanced pseudojujubogenin glucosyl rhamnoside, and 1.6-fold enhanced bacopaside N2 content in comparison with vector control plant, whereas in the knockdown lines of UGT79A18, we found 1.4-fold reduction in bacopaside II content, 3-fold reduction in the bacopasaponin D content, 2-fold reduction in the pseudojujubogenin glucosyl rhamnoside content, and 1.5-fold reduction in bacopaside N2 content in comparison with vector control. These results suggest that UGT79A18 is a significant UDP glycosyltransferase involved in glycosylating pseudojujubogenin and enhancing the pseudojujubogenin-derived bacosides.

Optimization of moving bed biofilm reactors for the treatment of municipal wastewater.

The properties of biocarriers significantly influence the performance of a moving bed-biofilm reactor (MBBR). This study aimed to assess the impact of media type, filling ratio, and hydraulic retention time (HRT) on biofilm formation and MBBR performance in both batch and continuous setups using real municipal wastewater. Two different media, high-density polyethylene (HDPE) and polypropylene (PPE), with varying surface area and properties were used. Biofilm growth and MBBR performance were monitored and optimized using response surface methodology. The effect of different media was investigated for three filling ratios of 20%, 40% and 60% and HRT of 4, 6 and 8 h. Results depicted a better biofilm growth on HDPE media in comparison to PPE carriers due to difference in media structure and surface properties. At all the conditions tested, HDPE media showed comparatively better performance for the removal of organic matter and nutrients than PPE media. The maximum organic matter removal efficiency was found as 77% and 75% at an HRT of 6 h and filling ratio of 40% for HDPE and PPE media, respectively. The ammonia removal was also found better for HDPE media due to its geometry and structure favoring the anoxic conditions with maximum removal of 89% achieved at 6-h HRT and 40% filling ratio. Overall, the system with HDPE media indicated more stability in terms of reactor performance than PPE carriers with variations in the operating conditions.

Biohydrogen from waste feedstocks: An energy opportunity for decarbonization in developing countries.

In developing economies, the decarbonization of energy sector has become a global priority for sustainable and cleaner energy system. Biohydrogen production from renewable sources of waste biomass is a good source of energy incentive that reduces the pollution. Biohydrogen has a high calorific value and emits no emissions, producing both energy security and environmental sustainability. Biohydrogen production technologies have become one of the main renewable sources of energy. The present paper entails the role of biohydrogen recovered from waste biomasses like agricultural waste (AW), organic fraction of municipal solid waste (OFMSW), food processing industrial waste (FPIW), and sewage sludge (SS) as a promising solution. The main sources of increasing yield percentage of biohydrogen generation from waste feedstock using different technologies, and process parameters are also emphasized in this review. The production paths for biohydrogen are presented in this review article, and because of advancements in R and D, biohydrogen has gained viability as a biofuel for the future and discusses potential applications in power generation, transportation, and industrial processes, emphasizing the versatility and potential for integration into existing energy infrastructure. The investigation of different biochemical technologies and methods for producing biohydrogen, including anaerobic digestion (AD), dark fermentation (DF), photo fermentation (PF), and integrated dark-photo fermentation (IDPF), has been overviewed. This analysis also discusses future research, investment, and sustainable energy options transitioning towards a low-carbon future, as well as potential problems, economic impediments, and policy-related issues with the deployment of biohydrogen in emerging nations.

Optimizing alkali-pretreatment dosage for waste-activated sludge disintegration and enhanced biogas production yield.

The rapid transition towards modernization and industrialization led to an increase in urban population, resulting in paramount challenge to municipal sewage sludge management. Anaerobic digestion (AD) serves as a promising venue for energy recovery from waste-activated sludge (WAS). Addressing the challenge of breaking down floc structures and microbial cells is crucial for releasing extracellular polymeric substances and cytoplasmic macromolecules to facilitate hydrolysis and fermentation process. The present study aims to introduce a combined process of alkaline/acid pre-treatments and AD to enhance sludge digestion and biogas production. The study investigates the influence of alkali pretreatment at ambient temperature using four alkali reagents (NaOH, Ca(OH)2, Mg(OH)2, and KOH). The primary goal is to provide insights into the intricate interplay of alkali dosages (0.04-0.12 g/gTS) on key physic-chemical parameters crucial for optimizing the pre-treatment dosage. Under the optimized alkaline/acid pre-treatment condition, the TSS reduction of 18%-30% was achieved. An increase in sCOD concentration (24%-50%) signifies the enhanced hydrolysis and solubilization rate of organic substrate in WAS. Finally, the biomethane potential test (BMPT) was performed for pre-treated WAS samples. The maximum methane (CH4) yield was observed in combination A1 (244 mL/g) and D1 (253 mL/g), demonstrating the pivotal role of alkali optimization in enhancing AD efficiency. This study serves as a valuable resource to policymakers, researchers, and technocrats in addressing challenges associated to sludge management.